Aerodynamic response of structures with parametric uncertainties

Uncertainties associated with the load effects and dynamic characteristics of wind-excited structures have been identified and discussed. Based on the available experimental data from laboratory and field study measurements the variability of the parameter space categorized as wind environment and meteorological data, wind-structure interaction and structural properties has been assessed. The probabilistic dynamic response of a wind-excited structyre has been expressed in terms of uncertain parameters. The influence of uncertainty in these parameters has been propagated in accordance with the functional relationships that relate them to the structural response. In this study, the propagation of uncertainty has been obtained by employing the Second-Moment and Monte Carlo simulation techniques. The dynamic response of a chimney subjected to aerodynamic loads is presented to illustrate the treatment of uncertainty in the parameter space. The mean and coefficient of variation of the peak chimney response, in terms of top deflections and associated base bending moments, exhibit close agreement between the Second-Moment and simulation techniques. A sensitivity analysis has been conducted which delineates the relative significance of uncertainty in the several parameters, related to both load effects and structural characteristics, on the overall uncertainty in the aerodynamic response of a chimney. The uncertainty associated with both response components suggests a need for further improvement in the modeling of wind-structure interaction, prediction of natural frequencies and damping, and reduction in the variability of extreme wind estimates. There are immediate applications of the procedures discussed in this paper for a variety of wind-sensitive structures.